The short answer
llms.txt is a plain-text file at the root of a website that summarizes the site and links its most useful pages, written for AI tools. It was proposed in 2024. Google has said it doesn't use it for search. It's cheap and harmless to add, but it won't fix a site that's unclear.
A heading with the business name, a one-line summary, and a list of important pages with a sentence each. Some sites add a longer llms-full.txt carrying the page text.
Lehvel publishes both, at lehvel.com/llms.txt and lehvel.com/llms-full.txt.
Google has said it doesn't use llms.txt in search, and adding one won't change rankings. Some AI tools read it when a user points them at a site. Whether the big assistants use it when answering customers is unclear, and site owners on Reddit report mixed evidence from their server logs.
If your site already says clearly what you do, where, and how to reach you, an llms.txt is a small, cheap addition. If it doesn't, fix the site first. An assistant reading a clear homepage learns more than one reading a summary file.
No. Nothing requires it.
Write a plain-text file with your business name, a one-line summary and links to your key pages, and put it at yoursite.com/llms.txt.
No. robots.txt controls crawling and the sitemap lists pages for search engines. llms.txt is a summary for AI tools.
No.
2 min readTo check what ChatGPT says about your business, open a Temporary Chat or a logged-out browser and ask what a customer would: "best plumber in [town]", "is [your business] open Sundays".
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